<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <!-- import CSS -->
    <link rel="stylesheet" href="https://cdn.staticfile.org/element-ui/2.15.9/theme-chalk/index.css">
    <style>

    </style>
</head>
<body>
<div id="app">
    <el-page-header
            style="background-color: #0095d7;color: white;
                    line-height: 60px"
            @back="goBack" content="修改轮播图">
    </el-page-header>
    <img :src="oldUrl" width="100"  alt="">
    <el-upload
            action="/upload"
            name="pic"
            limit="1"
            list-type="picture-card"
            :on-success="handleSuccess"
            :on-preview="handlePictureCardPreview"
            :on-remove="handleRemove">
        <i class="el-icon-plus"></i>
    </el-upload>
    <el-dialog :visible.sync="dialogVisible">
        <img width="100%" :src="dialogImageUrl" alt="">
    </el-dialog>
    <el-button type="success" @click="update()">修改轮播图</el-button>

</div>
</body>
<script src="https://cdn.bootcdn.net/ajax/libs/axios/0.21.1/axios.min.js"></script>
<!-- import Vue before Element -->
<script src="https://cdn.staticfile.org/vue/2.6.14/vue.min.js"></script>
<!-- import JavaScript -->
<script src="https://cdn.staticfile.org/element-ui/2.15.9/index.min.js"></script>
<script>
    let v = new Vue({
        el: '#app',
        data: function () {
            return {
                dialogImageUrl: '',
                dialogVisible: false,
                url:"",  //记录上传成功的图片路径
                oldUrl:""
            }
        },
        methods: {
            goBack(){
                history.back();//返回上一页面
            },
            handleRemove(file, fileList) {
                console.log(file, fileList);

                axios.get("/remove?url="+v.url).then(function(response){
                    v.$message("删除成功!");
                    //删除后url 应该清空  代表没有选择上传的图片
                    v.url="";
                })
            },
            handlePictureCardPreview(file) {
                this.dialogImageUrl = file.url;
                this.dialogVisible = true;
            },
            handleSuccess(response,file,fileList){
                //file.response得到服务器上传成功后相应的图片路径
                v.url=file.response;
            },
            update(){
                if (v.url==""){
                    v.$message("请选择上传的图片!");
                    return;
                }
                //得到需要修改的轮播图id
                let id = location.search.split("=")[1];
                //把id和url封装到对象中
                let banner ={id:id,url:v.url};
                axios.post("/banner/update",banner).then(function () {

                    //修改完成之后把之前的图片删除
                    axios.get("/remove?url="+v.oldUrl).then(function () {
                        //返回后台管理页面
                        location.href="/admin.html";
                    })
                })

            }
        },
        created:function () {
            //发请求通过地址栏中的id获取对应的图片路径
            axios.get("/banner/selectById"+location.search).then(function (response) {
                v.oldUrl = response.data;
            })
        }
    })
</script>
</html>